In many areas of industry, it is often necessary to reduce the pressure of fluids (both liquids and gases) within a pipeline. Fluid flow control valve systems are often used for this purpose. Various designs for fluid flow control valves have been presented in the art. For example, a plurality of tortuous fluid flow paths may be provided within a fluid flow control valve. As fluid passes through the tortuous fluid flow paths, the fluid is caused to change direction many times. Furthermore, as the fluid travels through the tortuous fluid flow paths, the overall cross-sectional area of the fluid flow path may increase to provide a decrease in the velocity of the fluid within the flow path. These devices are commonly referred to as “tortuous path trim devices.”
Tortuous path trim devices have been provided that include a plurality of substantially planar disks stacked on top of one another to provide a hollow, cylindrical structure. Such structures are commonly referred to as “valve trim disk assemblies.” Each disk generally includes a plurality of voids formed through the disk. The disks may be aligned and stacked together such that a plurality of continuous, tortuous fluid paths are provided by the voids in the disks that extend from the central region of the hollow, cylindrical valve trim disk assembly to the exterior of the valve trim disk assembly.
A valve trim disk assembly is typically provided within a body of a fluid flow control valve. The body of the fluid flow control valve is configured to direct the fluid from an inlet towards the hollow, cylindrical valve trim disk assembly. The valve also may be configured to direct fluid passing through the valve trim disk assembly to the exterior thereof towards a fluid outlet. The fluid flow control valve may include a piston configured to be inserted into the central region of the valve trim disk assembly, thereby interrupting fluid flow through the valve trim disk assembly and closing the valve.
Pressurized fluids contain stored mechanical potential energy. The valve trim disk assembly dissipates this energy by reducing the pressure and velocity of the fluid. As the fluid flows through the fluid pathways, the fluid flow may be turbulent. Turbulent fluid has associated pressure and velocity fluctuations that act upon the structural elements of the pipes and fluid control devices in which the fluid is flowing. These pressure and velocity fluctuations cause vibrations and noise. In many applications, noise is an undesirable or unacceptable characteristic of a fluid flow control device.
As a result, valve trim assemblies have been presented in the art having design features intended to suppress noise generated therein. Nonetheless, a substantially silent valve has yet to be discovered and incremental improvements in noise suppression are desirable.